DSL Reference Virtual Noise for Crosstalk Mitigation
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Solution Overview
Problem
Current DSL communication technologies face challenges with non-stationary noise, leading to unstable connections and performance issues due to crosstalk when transitioning between low power and normal operation modes, particularly in VDSL2 systems, where the long time periods required for power spectral density adjustments can be inconvenient and result in performance degradation.
Innovation Solution
The implementation of Reference Virtual Noise (RVN) is used to mitigate non-stationary noise by generating a noise level that reflects actual conditions in the cable binder, allowing for flexible transitions between low power and normal operation modes without significant disturbance, using RVN to determine bit loading and manage noise levels dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a line quickly transitions from low power mode back to normal operation, then the response time to service demands is improved, but the crosstalk generated suddenly increases which can significantly reduce performance of other lines and kick them out of synchronization
Solution Approach 1:
The patent applies preliminary action by performing a notification step before the actual power increase. The CO sends a notification to CPEs about an upcoming power spectral density increase, allowing them to prepare by adjusting their bit loading and power levels in advance. This prevents sudden crosstalk spikes that would otherwise occur during rapid mode transitions, resolving the contradiction between fast transition speed and crosstalk control.
2Object-generated harmful factors
If multi-step exit is used to gradually increase power spectral density, then the crosstalk impact on other lines is reduced, but the time required for transition increases to about 30-40 seconds
Solution Approach 1:
The notification mechanism allows CPEs to perform preliminary adjustments before the power increase occurs. This eliminates the need for lengthy multi-step transitions with 30-40 second delays, as CPEs can rapidly adapt their bit loading in response to the advance notification, enabling fast transitions without excessive crosstalk impact.
Solution Approach 2:
The system uses feedback through the notification mechanism where the CO informs CPEs of upcoming power changes. This feedback loop allows CPEs to adjust their transmission parameters dynamically, enabling faster convergence than traditional multi-step methods while maintaining stable operation and minimizing crosstalk disruption.
3Use of energy by moving object
If low power mode is used to reduce power consumption, then energy savings are achieved during idle periods, but connection stability deteriorates due to non-stationary noise behavior
Solution Approach 1:
By notifying CPEs in advance of power mode changes, the system allows them to prepare their transmission parameters before the transition occurs. This preliminary action maintains connection stability during low power mode transitions, preventing the non-stationary noise issues that would otherwise occur with abrupt power changes, while still enabling significant energy savings.
Data Source
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AI summary
A first digital subscriber line device (10, 14) to mitigate crosstalk noise on a signal to be transmitted over a transmission line of a network comprises a transceiver device (20) configured to transmit a reference virtual noise signal that is an estimation of noise on the transmission line to a second digital subscriber line device (10, 14) capable of being connected to the transmission line, wherein the transceiver device (20) is configured to receive a bit loading value of the signal that mitigates the crosstalk noise based on the reference virtual noise signal, wherein the transceiver device (20) is configured to transmit an update of the reference virtual noise signal at showtime, wherein the transceiver device is configured to receive a measure of noise of the transmission line of the network from the second device, wherein the transceiver device (20) is configured to receive the bit loading value based on the reference virtual noise signal for a plurality of modes of communication, and wherein the transceiver device (20) is configured to switch between the modes of communication, wherein at least one of the modes of communication is a power mode.